[Dru]

You probably have an electric quadrajet on you model, with all of the emissions garbage, unless you have removed it, and I doubt that thing is helping much.

Wires could have helped, but that would have been a very minimal increase if any.

Im curious about your cooling fan, you removed always running electric units? Or the stock clutch fan? The stock clutch fan would probably have been better as far as mileage.

Your ignition timing could have an affect on gas mileage, but I would guess if someone wanted to get real serious, I'd probably go about it as follows myself.

If you have the electric quadrajet trash it, and replace it with an older model, or for easier tunability, I'd go with a vacuum secondary Holley 650. You might get better milage with a well tuned older quadrajet, but there is definitely more work involved.

Trash the smog pump, and all emissions crap, disconnect the factory connection for the lockup converter in your transmission if you have one, and install an aftermarket trigger.

Buy a air/fuel ratio gauge, which works off of one or more O2 sensors, wideband better, and tune your engine to the best air/fuel ratio, so youre not running too rich and wasting gas.

Other than that, it just depends on how you drive also, and once you reach a good air/fuel ratio, there isn't much more you can do besides gearing.

Edit: your HEI distributor would need to be swapped for an older model also, if you have the elec quadrajet, and emissions crap.